How about trading parts?

As far as dealing with businesses in the US I think the problem may be there are restrictions and limitations to selling/shipping outside of the country. There are many more hoops to jump through to get something shipped out of the country. Then there is a fear that there is no US jurisdiction outside of the US. If you buy something from a US seller and your payment turns out to be fraudulant they lose and there is nothing they can do to prosecute you. You may be a great upstanding person but if you buy something from me, I'm not shipping it to you until I know for certain I have your money. As far as answering questions from email, many of the spam emails that show up in our In Boxes originate from overseas and aren't legitamite. They are scams. When you call, you are now a real person, not a scam.
As for your end of the deal-I wish you luck. I have been screwed a few times by ripoff artists in my own backyard. I could hunt them down and break their kneecaps if I wanted, but I don't. They could really screw you over pretty good and there is little you would be able to do unless you are willing to make the trip over here.
FWIW, there is a member on another forum from Venezuala that goes through the same problem so it's not just you.